Outlook doesn't require new att.net email password

I changed my att.net email account password through mail.yahoo.com.  The Yahoo mail phone app then required that I enter the new password to access my account.  But I also access that email account through Outlook on my computer.  Outlook didn't require that I enter the new password, and I still can send and receive emails on that account through Outlook.  This is concerning.  If the computer were stolen and someone could get past the device password, they could access my email account through Outlook, even if I changed the password on the account through mail.yahoo.com.  What's going on?